Retrievable bridge plug



March 25, 1969 M. D. KILGORE ET RETRIEVABLE BRIDGE PLUG Sheet of 2 Filed Sept. 26, 1966 INVENTORS Marion D. Kilgore Roberi C. Pu

mpelly ATTORNEY March 25, 1969 M. D. KILGORE ET AL 3,434,538

RETRIEVABLE BRIDGE PLUG Ro be H C. Pumpelly ATTORNEY Egg E ABSTRAQT UP THE DISCLOURE A retrievable bridge plug that is arranged to be run into a well bore to isolate a portion of the well bore. The bridge plug can be set in compression and/ or tension and includes, in addition to a deformable packing member, upper and lower toothed slips that are engageable with the wall of the well bore to prevent movement of the bridge plug therein. The bridge plug is run into the well bore on a running tool that is connected to the tubing string. The running tool is releasably connected to the bridge plug so that it can be removed therefrom after the bridge plug is set. A valve mechanism, carried by the bridge plug, is operated by the running tool. When the running tool is connected, the valve is open permitting fluid to pass through the mandrel to equalize the pressure across the bridge plug. The valve is closed upon removal of the running tool from the plug. A by-pass passageway extends through the bridge plug between the packing member and mandrel permitting the plug to be moved through the well bore more rapidly. A by-pass valve, carried by the mandrel closes the by-pass passageway when the bridge plug is set.

This invention is concerned with a well packer and is particularly concerned with a retrievable bridge plug.

A bridge plug is basically an isolation tool adapted to be run into an oil well and set to isolate a lower portion of the well from an upper portion upon which pressure operations, such as treating, acidizing, formation fracturing, squeezing, swabbing, testing, etc., are to be carried out. The tubular string upon which the tool is run and set is disconnected therefrom to expedite the above procedure.

The present invntion is concerned with a retriveable type of bridge plug wherein a disengageable running tool attaches the running string to the packer which may be reattached for retrieval of the packer or for movement and resetting at another level in the well.

SUMMARY OF THE INVENTION This invention provides an improved well packer or bridge plug for use in a well bore that includes a packer assembly; upper and lower slips and slip expanders on the packer assembly; a mandrel extending through the packer assembly; disengageable attachment means between the mandrel and the packer assembly, whereby the mandrel can be disengaged from the packer assembly and moved axially with relationship thereto; a passageway extending through the packer assembly; valve means carried by the mandrel arranged to open and close the passageway; a running tool attachable about the upper end of the mandrel and engageable with the valve means to move the same between open and closed positions; packing means including a deformable packing member encircling the mandrel; by-pass means between the packing means and mandrel; by-pass valve means carried by the mandrel for closing the by-pass means when the packer is set in the well bore.

Among the objects of this invention are the followmg:

ice

1) To provide an improved retrievable bridge plug of the compression type for increased pressure and temperature capability. Previous bridge plugs have generally been of cup-type construction with the inherent pressure limitations thereof and with the further disadvantage of abrasion on the cups due to movement in the casing as the tools are run or are repositioned in the casing.

(2) To provide a retrievable bridge plug of the compression type with increased capability for trouble-free running and retrieving.

(3) To provide a retrievable bridge plug with increased efiiciency and capability of reversal of the setting operationls to afford unseating and reseating for re-use in the wel (4) To provide a retrievable bridge plug with an internal valve and bypass arrangement for facilitating displacement of well fluids and cleaning of debris therefrom as the tool is run or retrieved.

(5) To provide a retrievable bridge plug of the character described in which the displacement of fluids during running and retrieving is directed to afford cleaning and washing of the working parts of the packer assembly durmg runmng or retrieving.

(6) To provide a retrievable bridge plug with an equalizing bypass channel which is automatically opened wheneYer the running tool is attached to the retrievable bridge p ug.

(7) An important object of the invention is to provide a tool which will automatically compensate for abnormal pressure differentials thereacross to further compress the packing element.

A suitable embodiment of the invention is shown in the attached drawings wherein:

FIGURES I and I-A comprise a quarter sectional elevational view of the bridge plug with running tool attached as it would appear while being run into the well,

FIGURE II is a transverse sectional view taken on the line 11-11 of FIGURE I;

FIGURE III is an elevational view of the upper J-slot showing the different positions of the upper gudgeon pin therein;

FIGURES IV and IV-A comprise a quarter sectional elevational view of the bridge plug as it would appear in set position in the casing;

FIGURE V is a transverse sectional view taken on the line V-V of FIGURE IV, and

FIGURE VI is an elevational view of the lower J-slot showing the different positions of the lower gudgeon pin therein.

Numeral references are employed to designate the various parts in the drawings and like numerals indicate like parts in the various figures of the drawings. When the tool is to be run into a well casting 1 (shown in FIGURES IV and IV-A), a running tool indicated generally as 3 is connected to a tubular string 2 at the mating threads 4.

The running tool 3 consists of an upper coupling 5 which has a counterbore 6, a lower face 7, and mating threads 8 for rigid connection of same to a collet housing 9.

The collet housing 9 is of tubular construction, with an inner bore 10 and a counterbore 11, and is rigidly connected to an upper J slot body 12 by the mating threads 13.

The upper J body 12 has an upwardly extending portion 14, which presents a downwardly facing shoulder 15, and has a J slot profile slot 16 (FIGURE III) milled or cast on the interior wall thereof.

An actuating collet 17 is slidably carried in the bore 10 of the collet housing 9 between the limits of the lower face 7 of the upper coupling 5 and the upwardly extending portion 14 of the upper J-slot body 12. The actuating collet 17 has therein an inwardly extending annular ring 18, having an upper face 19 and a lower face 20 thereon. There are a multiplicity of axial slots 21 milled through the wall of the actuating collet 17 and extending across the inwardly extended annular ring 18, thereby adapting a portion of the actuating collet 17 for deflection outwardly into the counter-bore 11 of the collet housing 9 as hereinafter described.

The mandrel assembly is indicated generally as 25 and includes the elements 26 to 69 inclusive. The guide cap 26 has a downwardly facing shoulder 27 rigidly affixed tc a valve mandrel 28 by the mating threads 29. The valve mandrel 28 has a reduced section 30 about the upper portion thereof, said reduced section 30 having tapered surfaces 31 at each end thereof. The valve mandrel 28 has a counterbore 32 in the lower end thereof and one or more ports 33 through the Wall thereof adapted for fluid communication from the counterbore 32 to the exterior of the valve mandrel 28 as hereinafter described. Seal means 34, such as resilient O-rings or the like, are spaced about mandrel 28 above and below the ports 33 for the purposes hereinafter mentioned. The valve mandrel 28 is rigidly connected to a gudgeon coupling 35 by the mating threads 36.

The upper portion of the gudgeon coupling 35 presents an upwardly facing surface 37 and carries thereon a gudgeon pin 38 near the upper extremity thereof. The gudgeon coupling 35 further carries seal rings 39 for a purpose hereinafter described, and has circulation ports 40 through the wall thereof for fluid communication between the interior of the mandrel assembly 25 and the exterior thereof.

The outwardly extending portion 41 below the circulation ports 40, has threads 42 thereon whereby a retaining sleeve 43 is attached thereto. The retaining sleeve 43 has an inwardly depending portion 44 therein which presents an upwardly facing shoulder 45 for purposes hereinafter described.

The outer tubular mandrel 46 is rigidly attached to the gudgeon coupling 35 by the mating threads 47, and has an outwardly extending portion 48 thereabout which presents an upwardly facing shoulder 49, and has circulation ports 50 through the wall thereof for fluid communication therethrough as hereinafter described.

The lower valve mandrel 51 is rigidly attached to the outer tubular mandrel 46 by the mating threads 52. A reduced portion 53 of the lower valve mandrel 51 is adapted to carry a mandrel seal assembly, hereinafter described, between the outwardly extended portion 48 of the outer tubular mandrel 46 and the upwardly facing shoulder 54. The upper counterbore 55 in the mandrel 51 has communication ports 56 through the wall thereof for fluid communication between the interior of the upper counterbore 55 and the exterior of the mandrel assembly 25. The reduced portion 53 also carries a seal ring 57 thereabout for sealing engagement with the mandrel seal assembly hereinafter described. The lower valve mandrel 51 extends downwardly and is terminated by the threads 58 and has a lower counterbore 59 therein. Counterbores 55 and 59 are separated by a partition 51a.

A lower J-slot body 60 is rigidly attached to the lower valve mandrel 51 by the mating threads 58 and has a counterbore 61 extending downwardly therein. Ports 62 through the wall of ]-slot body 60 establish communication from the counterbore 61 to the exterior of the mandrel assembly. Ports 63 provided through wall of body 60 at the lower end thereof establish communication between the counterbore 61 and the exterior of the mandrel assembly 25.

A frustoconical surface 64 is adapted for guiding purposes at the lower end of th lower J-slot body 60.

A lower J-slot profile slot 65 is cast, milled, or otherwise provided, in the exterior surface of the J-slot body 60, the shape of said lower J-slot profile 65 being shown as a planar development in FIGURE VI.

The lower valve mandrel 51 has threads 66 in the upper end thereof adapted for rigid and sealing attachment thereto of corresponding threads on an inner tubular mandrel 67 which extends upwardly therefrom inside the outer tubular mandrel 46 and is sealingly engaged by the seal rings 39 in the gudgeon coupling 35. The annular space between the inner madrel 67 and the outer mandrel 46 defines an outer bypass passage 68 therebetween. The interior of the inner tubular mandrel 67 defines an inner bypass passage 69. The functions of the outer bypass passage 68 and the inner bypass passage 69 will be described hereinafter in connection with the operation of the tool.

The upper valve assembly is indicated generally as and comprises the elements 76 to 85 inclusive. In said assembly there is a valve sleeve 76, slidably carried on the exterior surface of the upper valve mandrel 28 with the sliding action thereof being limited between the downwardly facing shoulder 27 of the guide cap 26 and the upwardly facing surface 37 of the gudgeon coupling 35. The valve sleeve 76 has a multiplicity of windows 7'7 therein spaced therearound and counterbores 78 immediately adjacent the upper end of said windows 77 and immediately adjacent the lower end of said windows '77, The valve sleeve 76 further has a multiplicity of slots 79 therethrough and spaced therearound which are adapted for communication with the ports 33 through the upper valve mandrel 28 when the valve sleeve 76 is in its lowermost position.

There is an outwardly extending shoulder portion 80 about the extreme lower end of the valve sleeve 76, which presents an upwardly facing surface 81 adapted for engagement with the downwardly facing shoulder 15 of the upper J-slot body 12. The valve sleeve 76 is also adapted for sealing engagement with the seal rings 34 carried about the upper valve mandrel 28. The seal rings 34 are adapted for sealing ports 33 when the valve sleeve 76 is in its uppermost position (see FIGURE IV).

There are a multiplicity of actuating pads 82 mounted in the windows 77 of the valve sleeve 76. The actuating pads 82 have axial flanges 83 extending upwardly and downwardly therefrom into the counterbores 78 of the valve sleeve 76. The spring members 84 are attached to the actuating pads 82 by means of the rivets 85 or the like, said spring members 84 extending laterally as shown in FIGURE II and coacting with the valve sleeve 76 to urge the actuating pads 82 inwardly.

As shown in FIGURE I, it should be noted that the actuating pads 82 are carried on the major diameter of the valve mandrel 28 and extend outwardly into diametrical interference with the inwardly extending annular ring 18 of the actuating collets 17 and that the inwardly extending annular ring 18 can not move upwardly in relation to the actuating pads 82 without collapsing outwardly into the counterbore 11 of the collet housing 9. Conversely, if the valve sleeve 76 is moved upwardly in relation to the valve mandrel 28, the actuating pads 82, urged inwardly by the spring members 84, could collapse inwardly into the reduced section 38 of the valve mandrel 28 (see FIGURE IV) and the inwardly extending annular rings 18 of the actuating collet 17 can be moved thereacross without interference.

The upper slip assembly, generally indicated at includes the elements 91-118 inclusive hereinafter described.

The setting sleeve 91 is slidably arranged around the outer tubular mandrel 46. The downward motion of the setting sleeve 91 with respect to the outer tubular mandrel 46 is limited by an outwardly extending portion 92 in contact with the upwardly facing shoulder 45 on the retaining ring 43. A slip take-up spring 93 is positioned between the upper end of the setting sleeve 91 and the lower end of the gudgeon coupling 35 to urge the members apart and is encircled by the retaining ring 43.

The setting sleeve 91 has one or more longitudinal slots 94 provided through the wall thereof for the purpose hereinafter mentioned.

The setting sleeve 91 is terminated at its lower end by a tapered Surface 95.

The slip rest 96 carries a pick-up pin 97 which is rigidly attached thereto by the companion threads 98 and the inner end thereof extends into slot 94. The slip rest 96 further includes a reduced diameter portion 99 encircling the setting sleeve 91 which is arranged to carry upper slip springs 100 thereabout and to limit the inward travel of a multiplicity of upper toothed slips 101 when said upper slips are in a retracted position. The upper slip housing 102 is attached to the slip rest 96 by the mating threads 103 and has a multiplicity of open-ended T-slots 104 formed through the wall thereof.

The slip rest 96 also carries one or more shear pins 105 attached rigidly thereto by the mating threads 106 and extending into matching holes 107 in the wall of setting sleeve 91 to thereby frangibly connect the slip rest to the setting sleeve. The axial position established between the slip rest 96 and the setting sleeve 91 by the shear pins 105 is such that the pick-up pins 97 are initially located at the upper end of the slots 94 in the setting sleeve 91. Such is a temporary position and exists only in the original running-in position and set position of the tool. When the packer is unseated as hereinafter described and the shear pins 105 are sheared, they serve no further useful function.

The upper slips 101 are suspended in the open-ended T-slots 104 by laterally projecting portion 108- thereon which prohibits axial movement of the upper slips 101 with relation to the upper slip housing 102, but allows radial movement therebetween.

The upper slips 101 have toothed serrations 109 on the outer periphery thereof adapted for penetrating engagement with the inner wall of the casing 1 when the packer is in an operating or set position. An outwardly and downwardly tapered inner surface 110 is provided on the upper slips 101, as shown.

The upper expander segments 112 are carried in a collapsed position around the outer tubular mandrel 46 and are urged thereto by a spring 113 encircling same. There is a lead-in taper 114 thereon adapted for co-action with the tapered surface 95 on the setting sleeve 91 to cause said setting sleeve 91 to move underneath the expander segments 112 when the setting sleeve 91 is moved downwardly with respect to said expander segments.

A depending portion 115 on the upper head segments 112 has a downwardly facing end 116. Threaded bores 117 are provided through portions 115 by which segment retainer screws 118 are affixed to each of the said upper head segments 112, the function of which is hereinafter described.

The packer body assembly is generally indicated as 120 and comprises the elements numbered 121 to 136 inclusive, hereinafter described.

The head cage 121 has a reduced interior diameter portion 122 adapted to be carried by the upwardly facing shoulder 49 of the mandrel assembly and to thereby suspend the upper expander head segments 112 by contact with the downwardly facing end 116 thereof. A counterbore 123 is provided in the upper end of the head cage 121 and a multiplicity of holes 124 are provided through the wall thereof which are adapted to coengage with the retainer screws 118, thereby holding the upper head expander segments 112 in fixed axial position, but allowing relative radial movement thereof when the tool is to be set in the casing 1.

There is a counterbore 125 provided in the lower end of the head cage 121 and one or more ports 126 are provided through the wall thereof for fluid communication between the counterbore 125 and the exterior of the tool. The upper thimble 127 is rigidly attached to the head cage 121 by the mating threads 128 and a packing 6 sleeve 129 is attached to the head cage 121 by the mating threads 130.

The packing sleeve 129 has a circulation counterbore 131 in the upper end thereof and a reduced interior diameter sealing bore 132 near the lower end thereof. A tapered shoulder 133 is provided for engagement with a mandrel seal means 140, hereinafter described. An outwardly extending portion 134, presenting an upwardly facing surface 135, is provided at the extreme lower end of packing sleeve 129.

A lower thimble 136 is slidingly disposed on the packing sleeve 129 and is limited in its downward axial motion by engagement with the upwardly facing shoulder 135. The upward relative motion of the lower thimble 136 is resisted by the compressive packing element 145, hereinafter described.

The mandrel seal assembly is generally designated as 140, and comprises a resilient seal lbody 141 and a support body 142. A tapered sunface 143 is provided on said body 142 that is adapted to engage the tapered shoulder 133 of the packing sleeve 129 and to transmit force from the mandrel assembly 25 into the packer body assembly 120. The resilient seal body 141 can be molded rigidly to the support body 142 or may be made so as to be snapped into place, or may otherwise be made replaceable. T-he resilient seal body 141 is adapted for sealing engagement with the sealing bore 132 of the packing sleeve 129 when the mandrel assembly 25 is moved downwandly with respect to the packer body assembly 120.

The main packing assembly is indicated generally at 145, and is illustrated as comprising a series of alternating resilient packing rings 146 and spacer rings 147. It will [be noted that the packing assembly 145 may be as illustrated or may consist of a one-piece packing element of braided heat-resistant asbestos or the like, or of any packing struc ture consistent with the environment of the well into which the element is to be run.

The lower anchor assembly is indicated generally at 150 and is comprised of the elements numbered 151 through 1 84, hereinafter described. The lower expander head 151 is attached to the lower thimble 136 by the mating threads 152 and extends downwardly therefrom. The lower expander head 151 has circulation ports 153 through the wall thereof for fluid communicating between the interior of the tool and the exterior thereof. There is an upper counterbore 154, an inwardly extending portion 155, and a lower countenbore 156 on the lower end of expander head 151 whose functions will be described in connection with the elements indicated hereafter. There is also a downwardly and inwardly extending outer tapered surface 157 on the lower end of the lower expander hea d 151 adapted for functions described herebelow.

The recovery sleeve 158 has an outwardly extending flange 159 thereon adapted for cooperative engagement with the inwardly extending portion in the lower expander head 151. There is also an outwardly extending portion 160 on the recovery sleeve 158 providing an upwardly facing shoulder 161, which is adapted for cooperative action with the inwardly extending portion 155 of the lower expander head 1 51. The recovery sleeve 158 extends downwardly through the interior of the lower anchor assembly 150 and has, at its lower end, a hole 162 therethrough adapted to receive a gudgeon pin 163 to hold said recovery sleeve 158 in axial alignment with the elements hereinafter described.

The gudgeon pin 163 is rigidly attached by the mating threads 164 to anchor cage 165. Anchor cage 165 has a multiplicity of windows 166 provided through the wall thereof with each of said windows 166 movably carrying therein friction pads 167. The friction pads 167 are movable radially in respect to the recovery sleeve 153 and the mandrel assembly 25, and are reiliently urged in an outward direction by means of springs 168. The outward limit of the movement of the friction pads 167 with respect to the anchor cage 165 is determined by the lateral flanges 169 thereon in contact with the anchor cage 165. The

springs 168 urge the friction pads 167 into frictional engagement with the wall of the casing when the tool is run into the well casing 1.

The anchor cage 165 further has an upwardly extending portion 170 carrying one or more key screws 171 attached thereto by the mating threads 172.

The key screws 171 coperate with a like number of axial slots 173 in the lower slip cage 174. The lower slip cage 174 has a lower counterbore 175 therein receiving the upwardly extending portion 170 to permit telescopic movement between the upwardly extending portion 170 of the anchor cage 165 and the slip cage 174. A take-up spring 176 is positioned between the upwardly extending portion 170 of the anchor cage 165 and an inwardly extending portion 177 in the lower slip cage 174.

There are a multiplicity of open-ended T-slots 180 in the wall of slip cage 174 arranged to carry a like number of upwardly facing lower slip segments 181 having laterally extending portions 182 thereon extending into slots 180.

The portions 182 engage the slip cage 174 to limit the axial L movement of the slip segments 181 with respect to the lower slip cage 174, but permit relative radial movement therebetween. The upper counterbore 178 of the lower slip cage 174 further encloses a multiplicity of lower slip springs 179 which are arranged to urge the lower slip segments 181 into a collapsed position when the packer is being run, but allows said lower slip segments 181 to move radially outward into anchoring engagement with the casing 1 when the packer is set.

The lower slip segments 181 further have toothed serrations 183 on the outer periphery thereof for penetrating engagement with the casing an upwardly and outwardly tapered surface 184 on each slip segment 181 is arranged to co-operate with the downward and inwardly extended tapered surface 157 of the lower expander head 151 so that the lower slip segments 181 can be forced outwardly into engagement with the casing 1 when relative telescopic movement of the lower expander head 151 and lower slip segments 181 occurs.

OPERATION The operation of the packer hereinbefore described is as follows:

When the running tool 3 is to be run in the well the running tool 3 is attached to the tubular string 2 by the mating threads 4 (FIGURE 1) Whenever the running tool 3 is removed from the mandrel assembly 25, or prior to attaching same thereto, the upper valve assembly 75 is always in the position shown in FIGURE 1V. When the mandrel assembly 25 is inserted into the running tool 3 with the actuating pads 82 in the collapsed position in the reduced section 30 of the mandrel assembly 25 as shown in FIGURE IV the upwardly extending portion 14 of the upper J-slot body 12 will pass over and around said actuating pads 82 and the downwardly facing shoulder 15 of the upper J-slot body 12 will contact the upwardly facing surface 81 of the valve sleeve 76. Further motion of the mandrel assembly into the running tool will result in a downward movement of the valve sleeve 76 relative to the upper valve mandrel 28, causing expansion of the actuating pads 82 as they ride over the lower tapered surface 31 of the reduced section 30.

The insertion of the mandrel assembly 25 into the running tool 3 continues until the gudgeon pin 38 assumes a psoitin 38a in the profile slot 16 of the upper jay slot body 12 (as shown in FIGURE III). As the tool is picked up by the tubular string 2 the running tool 3 and the mandrel assembly 25 are locked together with the gudgeon pin 38 assuming the position 38b (FIGURE III) with axial movement therebetween being limited by the distance between the two positions 38a and 38b. Thus, the upper valve sleeve 76 is held in a position wherein the slots 79 of the valve sleeve 76 are, through port 33, the inner bypass 69, and the communication ports 56, in communication with the portion of the oil well below the tool.

As the tool is suspended in the casing 1 by the running tool 3 the upper slip assembly is suspended from the retaining sleeve 43 by co-action of the upwardly facing shoulder 45 thereon with the outwardly extending portion 92 of the setting sleeve 91. The slip rest 96 is held in rigid position relative to the setting sleeve 91 by the shear pins protruding from the slip rest 96 into the holes 107 of the setting sleeve 91.

The packer body assembly is likewise suspended on the mandrel assembly 25 by the upwardly facing shoulder 49 of the outer tubular mandrel 46 in engagement with the portion 122 of the head cage 121. The portion 122 in turn carries the upper expander segments 112 by contact of the downwardly facing end 116 thereon with the portion 122 of the head cage 121.

The lower anchor assembly 150 is suspended from the packer body assembly 120 by the engagement of the upwardly facing shoulder of the packing sleeve 129 with the lower thimble 136. The recovery sleeve 158 is supported by the engagement of the inwardly extending portion 155 of the lower expander head 151 with the outwardly extended flange 159 of the recovery sleeve 158. The gudgeon pin 163, extending through the hole 162 of the recovery sleeve 158 carries the anchor cage 165, th lower slip cage 174, the lower slip segments 181 and associated structures. The gudgeon pin 163 also extends inwardly into the profile slot 65 of the lower J-slot body 60 to position 163a (see FIGURE VI).

As the tool is lowered into the hole the friction pads 167, in engagement with the casing 1, cause the gudgeon pin 163 to assume the position 163b, allowing slight telescopic action between the various parts described above but substantially holding the upper head segments 112, the packer body assembly 128 and the lower anchor assembly in an extended position with co-acting parts safely out of contact and free from running difficulties or presetting condition.

Setting When the required depth in the well has been reached the tool is set as follows:

The mandrel assembly 25 is picked up slightly by rais ing tubular string 2 and the running tool 3. This pla es the upper gudgeon pin 38 in position 38b (see FIGURE III) and the lower gudgeon pin 163 again in the position 163a (see FIGURE VI). Note that relative rotation can now be achieved between the gudgeon pin 163 and the lower J-slot body 60 but that no relative rotation can be achieved between the upper J-slot body 12 and the upper gudgeon pin 38. By the proper rotation (approximately turn to the right) and simultaneous lowering of the tubing string 12, the lower gudeon pin 163 will traverse through the profile 65 and the gudgeon pin 163 will eventually reach the approximate position 163a. Furthe lowering of the mandrel assembly with concurrent rotation to the left will place the gudgeon pin approximately in position 163d.

Simultaneously with the above actions the friction pads 167 have held the anchor cage 165, the lower slip cage 174 and the lower slip segments 181 in a fixed position against rotation and vertical movement relative to the casing 1.

The lower expander head 151 has been lowered simultaneously with the mandrel assembly 25 and the downward and inwardly tapered surface of the lower expander head 151 has contacted the upwardly and outwardly tapered surfaces 184 of the lower slip segments 181 caus' ing said lower slip segments to expand radially into an choring contact with the casing 1.

The setting sleeve 91, with its tapered surface 95 has also approached the upper head expander segments 112 with their upwardly facing lead-in taper 114. Further downward movement of the mandrel assembly 25 results in th setting sleeve 91 being introduced underneath the upper expander head segments 112, causing said upper expander segments to expand radially with respect to the mandrel. When contact between tapered surface 110 of the upper slips 101 is made with the tapered surfaces 111 of the upper expander segments 112 upper slips 101 are caused to be expanded radially into contact with the casing, resulting in a certain degree of compression in the slip take up spring 93.

The downward motion of the mandrel assembly 25 which results in the contact of the lower slip segments 181 and lower expander head 151 and the upper expander segments 112 and the upper slips 101 has also moved the mandrel seal assembly 140 downwardly in respect to the packing sleeve 129 and into the sealing bore 132 therein. When contact is made between the tapered surface 143 on the body 142 and the tapered shoulder 133 of the packing sleeve 129, further downward movement will result in a compressive force being applied on the packing assembly 145 through the upper thirnble 127 until the resilient packing rings 146 have been expanded outwardly into sealing contact with the casing 1.

The sealing engagement of the mandrel seal assembly 140 with the sealing bore 132 also effectively stops fluid communication from below the tool through the circulation ports 50, the outer bypass and the circulation ports 40. Communication to the exterior of th tool through the ports 126 is also stopped.

As further downward movement of the mandrel assembly 25 occurs after contact between the tapered surfaces 143 and 133 causing the expansion of the packing assembly 145, the upper expander head segments 112 are pulled downwardly by the retainer screws 118 disposed in the holes 124- of the head cage 121. A corresponding downward motion has been imparted to the upper slips 101, the upper slip housing 102 and the setting sleeve 91 with the slip take up spring 93 still in some degree of compression.

When complete packoff between the tool and the casing 1 has been achieved by compression of the packing assembly 145 the upper slips 101 in association with upper expander head segments 112 are in position to oppose any upward movement of the packing assembly 145 and associated structures if the downward force on the mandrel assembly 25 is relaxed or reversed.

The tool is now in set position with a positive compression type packolf achieved with the casing 1 and the outer bypass 68 effectively sealed against communication through the tool.

In shallow wells where the weight of the tubular string is not sufficient to give the required degree of compression to the packing assembly 145 or in deeper wells where crookedness of the hole or other conditions of the well becomes a factor in applying the weight of the tubular string, tension can be applied to the tool through the tubular string.

The upper gudgeon 38 in position 38]) may be employed to cause the mandrel assembly 25 and the lower J slot body 60 to move upwardly relative to the set tool until the gudgeon pin 163 assumes a position 163e. When this occurs the outwardly extending portion 160 of the recoverery sleeve 158 enters the lower counterbore 156 of the lower expander head 151 engaging the upwardly facing shoulder 161 on the sleeve 158 with the inwardly extending portion 155 of the lower expander head 151. The engagement causes an upward force to be applied to the packing assembly 145 through the lower expander head 151 and the lower thirnble 136.

Simultaneously with the above action the lower slip segments 181 have been moved upwardly with the lower expander head 151 but since the pressure between the tapered surface 157 of the lower expander head 151 and the tapered surface 184 of the lower slip segments 181 has been relaxed, a degree of compression will have been developed in the take-up spring 176. The compression occurs due to the axial movement of the key screws 171 in the axial slots 173 of the lower slip cage 174. The compression of the spring 176 keeps the lower slip segments 181 in position to immediately anchor the tool to the casing 1 when the tension force is relaxed or reversed.

After the packer is set as above described the running tool 3 may be removed from the tool as follows:

The tubular string 2 and the running tool 3 are lowered to place the gudgeon pin 38 in position 38a. The downward motion of the tubular string is then reversed accompanied by the proper rotation to cause the gudgeon pin 38 to assume a position approximately at 38c. In the upward motion of the running tool 3 contact is first made between the upper face 19 of the annular ring 18 and the actuating pads 82. Since the actuating pads 82 are backed up by the major diameter of the valve mandrel 28, they cannot move inwardly, and the first action is a downward motion of the actuating collet 17 in the inner bore 10 of the collet housing 9 termination upon contact occurring between said actuating collet 17 and the up wardly extending portion 14 of the upper J slot body 12. In this position the collet section of the actuating collet 17 has moved downwardly past the counterbore 11 of the collet housing 9 and as a result cannot expand outwardly; therefore, further upward motion of the tubular string will cause the valve sleeve 76 to move upwardly relative to the valve mandrel 28 until the actuating pads 82 can collapse inwardly under the urging of the spring members 84 into the reduced diameter section 30 of the valve mandrel 28 as illustrated by FIGURE IV. The upward movement of the valve sleeve 76 in respect to the valve mandrel 28 carries the slots 79 upwardly in respect to the ports 33 thereby closing the ports 33 and effectively controlling circulation through the ports 33, the inner bypass 69, the communication ports 56 thereby closing off the bore of the well casing below the tool.

The tubular string 2, any accessory packers or tools run therewith, and the running tool 3 can now be raised upwardly in the well and positioned for subsequent operations.

Normally, reconnection of the running tool 3 with the mandrel assembly 25 is a repetition of the original assembly procedures. However, it is possible that the approach of the running tool 3 for reconnection could inadvertently result in contact between the lower end of the upper J slot body 12 or the upwardly extending portion 14 thereof with the valve sleeve 76 or actuating pads 82 resulting in relative downward motion of the valve sleeve 76 with respect to the valve mandrel 28 causing the ports 33 to be opened to fluid communication through the slots 79. 'In this event, contact between the lower face 20 of the actuating collet 17 and the actuating pads 82, which are now protruding as shown in FIGURE I, would result in upward motion of the actuating collet 17 relative to the collet housing 9, placing the collet portion opposite the counterbore 11 in the collet housing 9. Downward force on the running tool 3 would then result in the radial expansion of the collet portion of the actuating collet 17 into the counterbore 11, allowing the inwardly extending annular ring 18 of the actuating collet 17 to pass below the actuating pads 82 and into a normally functioning condition.

With the running tool 3 removed up the well the retrievable bridge plug is securely anchored in the casing 1 (FIGURES IV and IVA) in sealing engagement therewith and with fluid communication from below the tool to above the tool effectively blocked by the mandrel seal assembly in sealing engagement with the packing sleeve 129 and by the upper valve assembly 75 in sealing engagement with the valve mandrel 28.

The retrievable bridge plug is securely anchored against downward movement in the casing 1 by the co-action of the lower expander head 151 and the lower slip segments 181 and against upward movement in the casing 1 by the upper head segments 112 co-acting with the upper slips 101. Fluid communication around the tool is effectively sealed off by the compressed packing assembly in sealing engagement with the casing 1.

This condition has been obtained by either tension or compressive forces applied by means of the tubular string 2. In installations where adequate weight or force can be applied through the tubular string 2 the upper gudgeon 38 assumes the position 38a, the lower gudgeon pin 163 assumes the position 163d, and the force necessary to compress the packing assembly 145 is applied through contact between the tapered surface 143 of the mandrel seal assembly 140 and the tapered shoulder 133 in the packing sleeve 129 and is applied to the packing assembly 145 through the upper thimble 127. This force is opposed by the lower thimble 136, the lower expander head 151 and the lower slip segments 181 in contact with the casing 1.

Tension forces may have been used to set the tool by upward movement of the tubular string 2 with the upper gudgeon pin '38 in position 38b, the lower gudgeon 163 in position 163e, and transmitted through the recovery sleeve 158 by contact of the upwardly facing shoulder 161 thereon with the inwardly extending portion 155 of the lower expander head 151 and thence into the packing assembly 145 through the lower thimble 136. This compressive force is opposed by the upper thimble 127, the head cage 121 and the combination of the upper expander segments 112 co-acting with the upper slips 101 to transmit the force into the casing 1.

An important usage of this tool is for isolating the lower portion of an oil well from a section above in order to apply certain pressure operations on a producing formation above the set tool. That portion of the oil well below the set tool may have a widely varying pressure proportional to the producing pressures of whatever zone is open thereto. That portion above the tool may contain fluids under widely varying pressures depending upon the type of operation to be carried out on the producing formations above the tool. Abnormally high pressures may be encountered in fracturing, squeezing or acidizing procedures or can be extremely low when swabbing, testing, etc., operations are carried out.

The present invention as described herein meets all requirements for an isolation tool inasmuch as its structure causes it to automatically compensate for differential thereacross when abnormal pressures are encountered either above or below the set tool. The differentials encountered exert a force over an area determined by the area of the mandrel seal assembly 140 between the mandrel assembly 25 and the sealing bore 132 of the packing sleeve 129. The piston-like structure of the mandrel assembly 25, in response to the differential, further compresses the packing assembly 145 and maintaining the upper or lower slip or anchoring assemblies in position to lock this compressive force in the packing assembly 145 when said differential is relaxed or reversed.

If the differential is from below the tool the force generated by the pressure acting on the area of the mandrel seal assembly 140' is transmitted from the lower jay slot body 60 through the gudgeon pin 163 in position 163e, through the upwardly facing shoulder 161 of the recovery sleeve 158 into the inwardly extending portion 155 of the lower expander head 151 and thence through the lower thimble 136 to the packing assembly 145 and is resisted by the immovable upper thimble 127, the head cage 121 and the combination of the upper expander segments 112 and upper slips 101 anchored to the casing 1.

If the differential is from above the tool a like force generated by action of the pressure over the area of the mandrel seal assembly 140 is transferred through the tapered surface 143 of the body 142 to the tapered shoulder 133 of the packing sleeve 129 and is transmitted downwardly through the upper thimble 127 to the packing assembly 145 and is resisted by the immovable lower thimble 136 supported by the combination of the lower expander head 151 co-acting with the lower slip segments 181 which rigidly anchor the tool in the casing 1.

When additional compressive forces due to abnormal differentials from above are applied to the packing assembly 145 the upper expander segments 112 may move downwardly in respect to the casing but the upper slips 101 remain in anchoring position under the urging of the compressed slip take-up spring 93 and immediately anchor such movement when the differential is relaxed or reversed. Similarly, if the additional compressive force is added to the packing assembly by abnormal differentials from below the packer the lower expander head 151 is moved upwardly in respect to the casing but the compression in the take up spring 176 maintains the lower slip segments 181 in anchoring position in respect to the lower expander head 151 and the lower slip segments 181 immediately anchor the entire assembly against reversal in motion when the differential is relaxed or reversed.

The packer is adequately supplied with both exterior circulation and equalizing passageways. As shown in FIG- URES I and I-A, as the tool is lowered in the hole, in addition to the circulation passageway around the outside of the un-set tool there are several passageways for displaced fluid to traverse upwardly through the tool with the additional objective of washing and cleaning the interior thereof as well as providing for the displacement of fluid.

Fluid may enter the lower end of the mandrel assembly 2 5 through the ports 63 in the lower jay slot body 60 and pass upwardly through the counterbore 61 thereof, outwardly to the interior of the packer body through the ports 62 into the body bypass 190. Fluid can also enter the body bypass through the circulation ports 153 in the lower expander head 151. Fluids entering the body bypass 190 and passing upwardly therethrough keep the interior of the tool free from debris, sand, and other foreign matter, by washing action. The fluids can pass from the body bypass 190 to the exterior of the tool through the ports 126 in the head cage 121 and thence upwardly in the annulus, through the circulation ports 50 in the outer tubular mandrel 46 and pass upwardly through the outer bypass 68 and thence through the circulation ports 40 to the annulus or through the communications port 56 in the lower valve mandrel 51 and thence upwardly through the inner bypass 69 and outwardly through the open upper valve assembly 75 through the ports 33 in the valve mandrel 28 and the slots 79 in the valve sleeve 76 to the annulus.

An additional objective and function of the present invention is the inner bypass 69 co-acting with the upper valve assembly 75 and serving as an equalizing mechanism by which a residual pressure differential existing between the portions of the well below and above the packer can be dissipated and equalized prior to retrieving the tool.

As described hereinabove the upper valve assembly 75 is always moved to open position when the running tool 3 is attached to the mandrel assembly 25 and such residual differentials will be equalized prior to retrieving the tool as hereinafter described.

Retrieving the packer When the packer is to be retrieved, either for removal to another section in the well for a repetition of the prior treatment, or for removal from the well entirely, the running tool 3 is reattached to the mandrel assembly 25 with the pressure difierential which may exist across the tool being equalized through the open upper valve assembly 75. The running tool 3 is lowered and rotated so that the gudgeon pin 38 reassumes the position 38b in the profile slot 16 of the upper J-slot body 12. The tubing string is then pulled upwardly with simultaneous rotation to the right to place the lower gudgeon pin 163 in the position 1630. Continued upward movement of the tubular string 2, the running tool 3 and the mandrel assembly 25 will cause re-engagement of the upwardly facing shoulder 45 of the retaining ring 43 with the outwardly extending portion 92 of the setting sleeve 91. The shear pins 105 (providing this is the first retrieval of the tool) then shear, permitting the setting sleeve 91 to move upwardly with respect to the slip rest 96 until the pickup pin 97 contacts the lower end of the slots 94 in the setting sleeve 91. Simultaneously the setting sleeve 91 has been pulled from underneath the upper expander segments 112, allowing the upper expander segments to collapse inwardly around the outer tubular mandrel 46 under the urging of the spring 113 and releasing the upper slips 101 from engagement with the casing 1.

The mandrel assembly 25 will have been simultaneously raised relative to the packing sleeve 129 and the mandrel seal assembly 140 pulled out of sealing engagement with the sealing bore 132 of the packing sleeve 129 allowing circulation to be established through the ports 126 in the head cage 121, the body bypass 190 and thence outwardly through either or both the circulation ports 153 in the lower expander head 151 or through the ports 62 in the lower J-slot body 60 and thence outwardly through the ports 63 in the J-slot body 60. The upward movement of the mandrel assembly 25 with respect to the head cage 121 will result in contact between the upwardly facing shoulder 49 on the outer tubular mandrel 46 with the portion 122 of the head cage 121. Further upward movement will then carry the upper head segments 112 (in a collapsed condition), the packing sleeve 129 and, through contact between the outwardly extending portion 134 of the packing sleeve 129 and the lower thimble 136 will remove the lower expander head 151 from contact with the lower slip segments 181, allowing the lower slip segments 181 to collapse out of engagement with the casing 1 in response to the urging of the lower slip springs 179. In the above described motion the gudgeon pin 163 has moved from the position 163a to the position 163a and thereby picks up the anchor cage 165, the lower slip housing 174, the lower slip segments 181, and associated structure.

The result of these total actions replaces the retrievable bridge plug in the position shown in FIGURE I and held in extended position with co-acting anchoring elements separated and with room allowed for axial expansion and radial relaxation of the packing assembly 145 out of sealing engagement with the casing and allowing bypass therearound for displaced fluid as the tool is moved upwardly in the hole.

It will be understood that other and further embodiments of the invention may be made without departing from the spirit of the invention.

Having described our invention we claim:

1. In a well packer, including a packer assembly, up per and lower slip and slip expander members on the packer assembly; a hollow mandrel extending through the packer assembly; a partition in the mandrel providing axial fluid flow passageson each side thereof; releasable attachment means between the mandrel and the packer assembly, whereby the mandrel can be disengaged from the packer assembly and moved axially with relationship thereto; a packer support sleeve carried by the packer assembly in spaced relationship to the mandrel; resilient packing material about the sleeve; port means through the wall of the mandrel above and below the partition, said port means communicating with the annular space between the mandrel and the packer sleeve and with the passages above and below the partition to provide an inner bypass through the mandrel; additional port means through the wall of the mandrel adjacent the upper end thereof communicating with the inner bypass; valve means about the mandrel arranged to close the additional port means; and a running tool arranged to be passed over the upper end of the mandrel and disengageably attached thereto, said running tool being engageable with the valve means to move same into position to open and close the additional port means.

2. The combination called for in claim 1 wherein the disengageable attachment between the running tool and the mandrel is a co-engaging ]-slot and gudgeon pin.

3. The combination called for in claim *1 with the addition of passage means above and below the packer support sleeve providing a bypass between the packer support sleeve and the mandrel.

4. The combination called for in claim 1 wherein the valve means comprises a sleeve slidable about the mandrel; a passage through the wall of the sleeve registerable with the additional port means; inwardly urged pads movable outwardly of the sleeve to engage the running tool, but being spring urged inwardly into an annular recess in the wall of the mandrel out of engagement with the running tool.

5. The combination called for in claim 4 with the addition of a collect sleeve slidably disposed in the running tool having collet fingers with shoulders therein engageable with the pads, and a recess in the wall of the running tool arranged to receive the collet fingers to allow the shoulders to go past the pads when the running tool is lowered thereover.

6. The combination called for in claim 1 wherein the disengageable attachment means between the mandrel and the packer assembly comprises a co-engaging J-slot and gudgeon pin.

7. The combination called for in claim 6 wherein the J-slot includes an upwardly facing shoulder engageable with the gudgeon pin to allow further expansion of the packer by upward movement of the mandrel.

8. The combination called for in claim 1 with the addition of a sleeve on the inner side of the mandrel above the partition providing an outer annular passage thereabout; and port means through the mandrel at the upper and lower end of the outer annular passage providing an outer annular bypass.

9. The combination called for in claim 8 with the addition of seal means carried about the mandrel arranged to be moved with the mandrel into sealing engagement with the bore of the packer sleeve to close the outer bypass and the bypass between the packer sleeve and the mandrel.

10. The combination called for in claim 9 wherein the packer sleeve is slidably suspended to the mandrel by shoulder means therebetween, whereby pressure from above or below the seal will cause the mandrel to move relative to the packer sleeve to thereby further compress the packing material.

11. In a bridge plug for use in a well bore, a running tool; a mandrel extending through said plug; releasable connection means between said running tool and mandrel; packing means including a deformable packing member encircling said mandrel; setting means on said mandrel for deforming said packing member into sealing engagement with the wall of the well bore, said setting means including upper and lower wall gripping slips movable into holding engagement with the wall of the well bore; a passageway in said mandrel providing communication from below said packing means to above said packing means when said packing member is deformed into engagement with the wall of the well bore; valve means on said mandrel movable between positions opening and closing said passageway, said valve means being engageable with and movable by said running tool, said passageway being open when said running tool is connected with said mandrel to equalize the pressure in the well bore above and below said packing means; by-pass means between said packing means and said mandrel; and, bypass valve means engageable with said packing means to close said by-pass means when said packing member is deformed.

12. The combination of claim 11 wherein said mandrel has an annular recess on the exterior thereof; and, wherein the valve means on said mandrel comprises a sleeve member slidingly disposed on said mandrel for movement between positions opening and closing the passageway in said mandrel, inwardly urged pads carried by said sleeve member engaging said mandrel retaining said sleeve member in the position closing said passageway when disposed in said annular recess and engaging said running tool to move said sleeve member to the position closing said passageway when said running tool is disengaged from said mandrel, and a shoulder on said sleeve member engaging said running tool to hold said sleeve member in the open position opening said passageway when said running tool is connected with said mandrel.

13. The combination of claim 12 wherein said running tool is hollow and has an annular groove in the interior wall thereof; upper and lower stop means located on opposite sides of said annular groove; and, a collet sleeve disposed between said stop means including a resilient portion and an abutment engageable with said pads located on the interior of said resilient portion, said abutment being adjacent said annular groove when said collet sleeve is in engagement with said upper stop means,

whereby said resilient portion moves into said annular 15 groove to permit movement of said abutment past said pads in a downwardly direction and being in engagement with the interior of said running tool when said collet sleeve is in engagement with said lower stop means, whereby said abutment is prevented from moving past said pads until said pads move into the annular recess in said mandrel.

References Cited UNITED STATES PATENTS 3,249,149 5/1966 McGowen 166-134 X 3,288,219 11/1966 Young et a1 166-134 X 3,306,360 2/1967 Young 166-131 X 3,308,886 3/1967 Evans 166-134 13,339,637 9/1'967 Holden 166-131 X 3,356,142 12/1967 Crow et a1. 166-134 DAVID H. BROWN, Primary Examiner.

US. Cl. X.R. 

